TG-FTIR study of pyrolysis products evolving from dyestuff production waste

Solid waste from dyestuff production is Classified as 'hazardous waste'. The thermal degradation of a dyestuff residue was studied in an inert atmosphere using Thermogravimetric Analysis Coupled with Fourier Transform infrared Analysis (TG-FTIR). A heating rate of 30 degrees C/min was applied, with final temperature of 950 degrees C. A total weight loss of 35.1 wt% was observed, and the temperature trend of evolving gaseous products, Such as CO2, CO, H2O, HCN and SO2, Was investigated. When heated in an inert atmosphere, the dyestuff residue starts decomposing below 200 degrees C, while reaching a peak Fate in volatiles' evolution around 257 degrees C. Sulphur and nitrogen evolve as SO2 and HCN, respectively. Also other gases and vapours, such as CO2, CH3OH and H2O are detected. At higher temperatures several compounds can still be monitored (temperature of maximum FTIR signal): methane (500 degrees C) Carbon dioxide (650-950 degrees C) and carbon monoxide (900 degrees C) Hydrogen chloride was not detected in this experiment. (C) 2008 Elsevier B.V. All rights reserved.